1. Field of the Invention
The present invention relates to an optical transmission mechanism for connecting a chip to an optical transmission path defined in a substrate of a circuit board when the chip is mounted on the substrate. Also, the invention relates to a chip mounting method utilizing the mentioned optical transmission mechanism.
2. Description of the Related Art
Computer systems such as main frames have usually employed electric wires printed on a board so as to transmit signals between chips. However, the transmission velocity of electric signals has a limit, so that faster calculation or processing cannot be expected with electric wires anymore.
Optical transmission is proposed to transmit signals between chips. The implementation of optical transmission is supposed to realize a faster signal transmission so that calculation or processing can be accelerated.
In order to implement optical transmission between chips on a circuit board, light emitting and/or light detecting elements on the chips need be optically coupled to optical transmission paths such as optical fibers and optical waveguides in the substrate of the circuit board. For example, an optical fiber may be used to connect a light detecting element to an optical waveguide in a substrate of a circuit board and to likewise connect a light emitting element to an optical waveguide. One ends of the respective optical fibers are adhered to the chip at receiving bores leading to the light emitting and detecting elements, while the other ends of the optical fibers are adhered to the substrate at receiving bores leading to the optical waveguides.
When a chip is mounted on a substrate of a circuit board with the above-mentioned structure, optical fibers are first adhered to either of the chip or the substrate. The optical fibers then need be inserted into receiving bores on the other of the chip or the substrate. The chip must be positioned with higher accuracy with respect to the substrate so as to prevent failure in inserting the tips of the optical fibers in the receiving bores. Also, if the space between the receiving bores in the chip is smaller or larger than that of the substrate, positioning the chip with higher accuracy to insert the tip of one of the optical fibers in the corresponding receiving bore cannot help insert the tip of the other of the optical fibers to enter the corresponding receiving bore.